Air cavity packages are usefully employed to house semiconductor die and other microelectronic devices, particularly those supporting RF functionalities. Air cavity packages are fabricated in a variety of different manners, with different manufacturing approaches associated with varying benefits and drawbacks. In one common approach for manufacturing leaded air cavity packages, a discretely-fabricated piece commonly referred to as a “window frame” is bonded between the package leads and a base flange. The window frame is produced from a dielectric material, such as a ceramic, to provide electrical insulation between the base flange and the package leads. The window frame may have a rectangular planform geometry and a central opening, which defines an outer perimeter of the air cavity when the air cavity package is assembled. Prior to attachment of a lid or cover piece, one or more microelectronic devices are positioned within the air cavity and bonded to the base flange, which may serve as a heat sink and, perhaps, as an electrically-conductive terminal of the package. Afterwards, the microelectronic devices are electrically interconnected with the package leads by, for example, wirebonding. The cover piece is then bonded over the window frame to sealingly enclose the air cavity and complete fabrication of the air cavity package.
In another air cavity package manufacturing approach, a molding process is carried-out to form a molded package body over and around selected regions of the base flange and package leads in place of the above-described window frame. Along with an exposed upper surface of the base flange, the molded package body defines an open air cavity in which one or more microelectronic devices are subsequently installed. After installation of the microelectronic devices and interconnection with the package leads, a cover piece is positioned in the air cavity and bonded to the molded package body to complete the package fabrication process. Utilizing such a mold-based manufacturing approach, so-called “molded air cavity packages” can be fabricated in a manner similar to the above-described, window frame-containing air cavity packages, but with greater process efficiencies and at lower manufacturing costs. These advantages notwithstanding, certain limitations continue to hamper processes for manufacturing molded air cavity packages, as conventionally performed. Such limitations may generally relate to difficulties encountered in maintaining precise alignment between package components prior to and/or through the molding process. Additionally, in the context of conventional molded air cavity package fabrication processes, it may be difficult to ensure the formation of reliable, high integrity seals between bonded components, as may be critical to preserve the sealed environment of the air cavity over the package lifespan in certain applications.
For simplicity and clarity of illustration, descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the exemplary and non-limiting embodiments of the invention described in the subsequent Detailed Description. It should further be understood that features or elements appearing in the accompanying figures are not necessarily drawn to scale unless otherwise stated. For example, the dimensions of certain elements or regions in the figures may be exaggerated relative to other elements or regions to improve understanding of embodiments of the invention.